(a) Field of the Invention
The present invention relates to a method for determining malfunction of a pressure sensor. More particularly, the present invention relates to a method for determining malfunction of a pressure sensor in a fuel tank.
(b) Description of the Related Art
Generally, a pressure sensor is mounted in a fuel tank for measuring a pressure of a fuel evaporation gas therein and detecting a leakage of the fuel tank. Evaporation gas in the fuel tank is captured in ordinary times and, when an engine starts, the evaporation gas is transmitted to a surge plenum and ignited in the engine.
Malfunctions of the pressure sensor mounted in the fuel tank include a malfunction by disconnection of a circuit of the sensor, a malfunction by a short, and a stick malfunction. The stick malfunction means that a voltage output from the sensor is locked up as one value because of an error occurrence of a current circuit in the sensor.
According to a method for determining malfunction of a pressure sensor of the prior art, the malfunction by a disconnection of a circuit of the sensor and the malfunction by a short can be determined but the stick malfunction cannot be determined.
Therefore, in a case that the fuel leaks from the fuel tank, when there is a stick malfunction the sensor determines that the fuel does not leak and thus the sensor outputs an error value. Therefore a problem occurs in that the leakage is not detected. In addition, in a case that the fuel does not leak from the fuel tank, when there is a stick malfunction the sensor determines that the fuel leaks and so the sensor outputs an error value. Therefore a problem occurs in that an engine warning lamp is erroneously turned on.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.